I have searched quite a bit and all the treads I have found on ice tires, but I haven't found any that explain the difference between screws and studs...more like what would work best for different types of riding. I am new to winter riding, so I am looking for advice on whether I should go with screw or studded tires on my 400S. No racing, very little black ice, mostly snow covered ice or hard pack. I have heard that screws would be fine for just tooling around (even in the snow) and I have heard that studs would be needed. In summary, I need something that works very well in the snow or snow covered ice, but will give me some traction on bare ice if needed. Any ideas? Edit: when I say studs, I mean something like Best Grip Nails studs.